A capacitive encoder works by measuring the change in capacitance from the change in dimensions of the capacitor. A capacitive encoder uses the change in capacitance value of a capacitor as a means to measure displacement. Typically, the capacitive sensor’s principle elements are arranged so that the capacitance changes as a moving elements displace relative to the stationary plates of the capacitor.
- Typically comprises of three main elements; a transmitter, conductive plates separated by a non-conductive material and a receiver board.
- Capacitance varies in proportion to the distance of the plates (d), as well as their overlap (A).
- Displacement can be measured axially (variation in d) or in the planar direction of the plate overlap (variation in A).
Strengths and weaknesses of a capacitive encoder
| Strengths | Weaknesses |
| Compact, low power | Significant temperature & humidity conflicts, sensitive to foreign matter. |